Lutra sumatrana was first described by Raffles in 1822 as Lutra barang; by Gray in 1865 as Barangia sumatrana; and Lutra lovii by Gunther 1876. Phole (1920) identified two subspecies L. s. lovii and L. s. brunnea. However, there is dispute about its authenticity (Pocock 1941). Recent genetic studies have confirmed it as a single species related to Lutra lutra (Koepfli et al. 2008).

Justification:
This species is considered to be Endangered due to past population declines. Based on estimated of rates of decline, this species is suspected to have declined by up to 50% in the past 3 generations (30 years) due to illegal poaching and hunting, pollution, bycatch and prey depletion due to over fishing. The current rates of decline are suspected to continue into the future and further threaten this species. In its entire range the hairy nosed otter is under increasing pressure due to intensive poaching. In Cambodia, around the Tonle Sap Lake, poaching of otters and other wildlife are common practice (Somanak 2007). In Viet Nam, otters are hunted for illegal wildlife trade, for meat and medical use. Similar is the case in other range countries. The principal threat to the fauna of Southeast Asian region is the burgeoning human population, and resultant biomass demand which puts pressure on natural resources. Unavailability of adequate prey species and suitable undisturbed habitat are putting additional pressure on all wildlife species including hairy-nosed otter. From these it is concluded that the hairy-nosed otter is under stress due to its restricted range, in which its habitat is under constant pressure and that there is every possibility of reduction in its population which has been inferred and future population is suspected to be under decline which may lead to decline in the area of occupancy, extent of occurrence and habitat quality. Combining with all these factors, extensive illegal exploitation of the species may lead to its extinction unless appropriate conservation measures taken. Therefore, the species have been evaluated as Endangered.

The hairy-nosed otter (Lutra sumatrana, Gray 1865) is the rarest and least known among the five species of otters occurring in Asia. It is endemic to South Asia. The type specimen came from Sumatra. Once believed to be extinct, the hairy nosed otter has been rediscovered from many parts of Southeast Asia such as Thailand, Viet Nam and Cambodia. Historically, it occurred from southern Indochina to Malaysia (Sebastain 1994, 1995) and Thailand (Lekagul and Mcneely 1988, Kanchanasaka 2000). In Thailand it has been reported from Phru Toa Daeng Peat Swamp Forest (Kanchanasaka et al. 1998). From Viet Nam it has also been reported from U Minh Thuong Nature Reserve in Mekong Delta (Nguyen et al. 2001, Nguyen 2005, Nguyen et al. 2007) and from Cambodia it has been reported from Tonle Sap wetlands (Long 2000, Poole 2003, Olsson 2007). It has been reported from Malaysia at Terengganu in 2003 and from Maur in 1995. It has been recently reported in Sumatra, Indonesia (Lubis 2005). Historical records of its occurrence comes from the coast off of Penang Island (Harrison 1984), and from accidental road kill in Brunei in 1997 (Sasaki 2006). Historically it has also been reported from Myanmar as evident from the skin present in the British museum. From this, the possible range of hairy-nosed otter can be worked out which is eastward from Northeast India (Indo-china), Myanmar, Thailand, Cambodia, Viet Nam, Lao PDR, Brunei, Malaysia and Indonesia.

In its distribution range the species is considered as rare. It has been studied in Phru Toa Daeng Peat Swamp Forest in Thailand (Kanchanasaka et al. 1998), U Minh Thuong Nature Reserve in Viet Nam (Nguyen et al. 2001, Sage et al. 2004) and in Tonle Sap from Cambodia (Poole 2003, Heng 2007). However, their abundance or group sizes are relatively not known. In U Minha National Park though it was estimated that there were around 50-230 individuals. The species is believed to be extremely rare in Peninsular Malaysia (Sebastian 1995) and reported from scattered localities in the Borneo (Payne et al. 1985).

In Thailand it lives in Phru Toa Daeng Peat Swamp Forests (Kanchanasaka et al. 1998). In Viet Nam it has also been reported from the low lying peat swamp forests of U Minh Thuong Nature Reserve in Mekong Delta (Nguyen et al. 2001, Sage et al. 2004) and from Cambodia it has been reported from Tonle Sap wetlands (Poole 2003, Heng 2007). It inhabits freshwater and coastal areas, especially mangroves in Indonesia. Wayre (1974, 1978) considered that the Hairy-nosed otter mainly inhabited mountain streams above 300 m, Medway (1969) recorded it in the sea off Penang.

The hairy nosed otter principally predate on fish (85.5%) followed by water snake and they also supplement their diet with frog, lizard, turtle, crab, mammal and insect, although these may not be that important in its diet (Kanchanasaka 2007). Fish belonging to the families Channidae, Belontiidae, Anabantidae, Notopteridae, Synbranchidae, Clariidae, Nandidae, were identified in the fecal samples from Thailand. The main prey selected were three-spot gourami (Trichogaster trichopterus), common climbing perch (Anabas testudineus), and snakeheads (Channa sp) (Kanchanasaka 2007).

Not much is known about its breeding behaviour but there is indication that it breeds in November-December in the Mekong delta. Kanchanasaka et al. (2003) found that gestation was around 2 months as with other otters, and cubs were seen in December to February, and one family observed consisted of both parents and a cub.

The hairy-nosed otter has limited distribution range. In Thailand, the otters are found in the Toa Daeng peat swamp forests, and also from near the mouth of the Bang Nara River which is low lying and tidal. In Viet Nam, the species have been reported from low lying peat swamp forests dominated by Melaleuca cajuputi in lower Mekong. In Cambodia, the species mainly live around the Tonle Sap Lake where the otters live mainly in the flooded forest and scrub surrounding the lake. Like many predators the hairy-nosed otter occurs in low density and the number and frequency of sightings are very few.

In recent years, the tropical peat swamp forests are under severe threat due to fire and other anthropogenic activities such as plantation for oil palm, food crops such as rice, corn and soyabean, and fish farming. In Viet Nam the entire Mekong Delta has been converted into rice fields reducing the habitat of otter and other wildlife species into few pocks. In Malaysia, fire reduced 70% of the Binsulok Forest Reserve and 10% of the Klias Forest Reserve. This has affected the surrounding environment and the biodiversity. In Indonesia over the last 20 years, the ecosystem has been reduced from almost 30 million hectares to only about 15 million hectares, and most of what remains has already been logged selectively. Such levels of habitat modification have profound effect on the native biodiversity.

In its entire range the hairy-nosed otter is under increasing pressure due to intensive poaching (Yoxn 2007). In Cambodia, around the Tonle Sap Lake, poaching of otters and other wildlife are common practice (Somanak 2007). In Viet Nam otters are hunted for illegal wildlife trade, and also for meat and medical use. Similar is the case in other range countries.

The principal threat to the fauna of Southeast Asian region is the burgeoning human population, and resultant biomass demand which puts pressure on natural resources. Unavailability of adequate prey species and suitable undisturbed habitat are putting additional pressure on all wildlife species including hairy-nosed otter.

Lutra sumatrana is listed in Appendix II of the CITES. It is legally protected in all the range countries. In Thailand all the otter species have been protected since 1961 under Wild Animals Preservation and Protection Act and are listed as endangered species in Thailand Red Data Book (Nabhitabhata and Chan-ard, 2005). In Viet Nam, otters are protected and their hunting and use is strictly banned. In Cambodia, the hairy-nosed otter is listed as "Rare" and is fully protected. In Sarawak all otter species are protected by the First Schedule [Section 2(1)] PART II on Protected Animals from the Wild Life Protection Ordinance, 1998.

Poole, C. M. 2003. The First Records of Hairy-Nosed Otter Lutra sumatrana from Cambodia with Notes on the National Status of Three Other Otter Species. Natural History Bulletin of the Siam Society 51(2): 273–280.